The link you provided doesn't clarify anything. Can you provide more information?

To be clear, I am talking about a cease-and-desist letter which was enforced, not merely complied with. That is to say, somebody received such a letter, and they said "No," and then the company went legal on them, proceeding all the way through the verdict, and won.

I'm not saying such things have never happened. I am saying that the widespread perception that (i) they happen all the time and (ii) are legally unassailable is based on little to no evidence, and that certain events like the Gygax/TSR situation are cited as evidence when they're not.